The objective of the experiments described in this proposal is to identify, isolate and determine aspects of the molecular structure of the beta-adrenergic receptor. This is an initial and necessary first step in order to determine the mechanism by which catecholamines activate adenylate cyclase in the plasma membrane of responsive cells. Work will be initiated on the beta-receptor-adenylate system of the nucleated avian erythrocyte ghost, a useful source of relatively pure plasma membranes. Several methods will be used to isolate the specific catecholamine receptor, using chemically stable derivatives of beta-receptor antagonist. These methods are: (a) insitu specific derivatization of the receptor using affinity and photo-affinity labels; (b) immunoprecipitation of the receptor from detergent extracts of plasma membrane using dinitrophenyl (DNP) derivatives of receptor antagonists and anti-DNP antibody; (c) ultracentrifugation of detergent solubilized receptor-DNP ligand complexes with anti-DNP (or Ferritin conjugated anti-DNP antibody); (d) affinity chromatography. The molecular size, subunit structure, and molecular composition of the receptor will be determined. Antibody to the receptor will be prepared for the purpose of using Ferritin conjugates to determine distribution on the surface of responsive cells. The experiments will increase our understanding of catecholamine beta-receptors, which function, in controlling heart rate, the metabolic state of liver and muscle and other autonomic functions of the sympathetic nervous system.